Digital Amati project

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I have been looking at the digital Amati project recently, it seems it is based on Francois Denis writings, I have already used his method to draw a few different forms, and he has a program on his website describing the process for drawing an Andrea Guarneri Viola which I have found very useful as a reference for the processes in my own drawings.

Has anybody used the digital Amati program much?

Does the program allow you to then create a drawing from the codes in digital form?

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The Benifit is that you can make subtle changes to your forms, make instruments slightly wider in the cc for example without having to redraw everything, just type in the numbers and press a button, if you don't like it just click undo.. this can be very useful, especially for the design of violas for example, where there is a large fluctuation in sizes.

I am definitely going to experiment with this.

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I understand what it can do, what I don't understand is why you would want to do it. I am ignorant not argumentative. It would seem if you have a very good form, then why change it - just because you can?

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I understand what it can do, what I don't understand is why you would want to do it. I am ignorant not argumentative. It would seem if you have a very good form, then why change it - just because you can?

It may not be a good form! For example, if you wanted to design your own small viola based of some of Helen Michetschlager's ideas you could make a form and instrument around it, but then after playing it in decided that you wanted to experiment with the upper bout being a little wider, you have everything there and saved and it would be a very simple tweak to adjust things. All just speculation but you get the idea.

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How is the program directed specifically at violin makers and not geometry in general? Can I draw the outline of the instrument instead of the inner mold? How about drawing scrolls? I would love a program that allows me to draw on the screen just as with a compass and ruler (that I understand) but this program is rather directed at programmers? Like the idea but the execution seems a bit over my head (patience).

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The program is, in fact, about geometry in general -- if you have a look at the Strad article, one of the highlighted quotes is that it is just a programmable straightedge and compass. It is for implementing the geometrical constructions you see in instruments, furniture, paintings, and lots of Euclidean math exercises----you could figure out how to draw a square with a straightedge and compass, but how about a pentagon? (It can be done, exactly.)

What is specific to the program is my "pre coding" of a variety of constructions found in François Denis's remarkable book. Then you don't have to remember them, you just invoke them with the relevant parameters.

How are gouges, chisels and planes "directed specifically at violin makers and not woodworking in general"? There is a similar question for you. It's a tool, and every one of them has a learning curve accompanying it, the steepness of that curve determined by the tool, the user, and the task. I've used it to repeat François's constructions, and to do some new ones. The most complicated use so far is to draw the arching for a cello belly and back, guided by drawings in the Sacconi book.

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How is the program directed specifically at violin makers and not geometry in general? Can I draw the outline of the instrument instead of the inner mold? How about drawing scrolls? I would love a program that allows me to draw on the screen just as with a compass and ruler (that I understand) but this program is rather directed at programmers? Like the idea but the execution seems a bit over my head (patience).

My assistant and I were thinking the same thing a week ago. It would be great if there was a more user friendly version - a digital ruler and compass.

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How is the program directed specifically at violin makers and not geometry in general? Can I draw the outline of the instrument instead of the inner mold? How about drawing scrolls? I would love a program that allows me to draw on the screen just as with a compass and ruler (that I understand) but this program is rather directed at programmers? Like the idea but the execution seems a bit over my head (patience).

2 hours ago, Guy Harrison said:

My assistant and I were thinking the same thing a week ago. It would be great if there was a more user friendly version - a digital ruler and compass.

Harry can correct me if I'm wrong here -

The program that does the drawings is called the Geometry Engine, which is a program that Harry wrote. It's basically a digital version of a compass and straightedge, but you have to be able to describe the relationships between centers, arcs, and lines in mathematical terms.

The idea of a visual ruler and compass already exists in many forms, like SketchUp, for example - I've used that heavily, but you have to know how to dumb it down to use it because the defaults are for doing much more complicated 3D rendering. There are other free programs out there to do similar things, although it's been so many years since i looked I don't know what they are now.

The real benefit of using the Geometry Engine to me is that it is programmable, which means you can describe the relationships among the various parts of the drawing and then easily manipulate them. In other words, in the program that I use (I wrote my 'four circle' thing into the geo engine) I can, for example, change the width of the waist, which automatically changes the location of the points of the corners, which in turn changes the arcs of the curves of the corner blocks. To do this by hand takes some work, but on the computer it is just changing one number.

Last month I was sans computer for a week, and I had an encounter with an amazing violin, which I decided I had to "copy". This meant deconstructing the design, which I did using pencil and paper, but it took me about 4 hours. If I had my computer it would have taken less than 10 minutes - and I could have just printed out a drawing at the correct size to make a template from.

There are some parts of the program specifically for violin makers - for instance Harry has created a function that will add a margin to a finished mold shape, so if you draw the inside of the ribs it will create an outline based on that. You can also instruct it to measure between any parts of the drawings.

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I should say that the Geo engine is easily one of the most important and useful tools that I have. It may not be for everyone, but if you can manage to figure out how to use it, it's a powerful game changer.

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The program is, in fact, about geometry in general -- if you have a look at the Strad article, one of the highlighted quotes is that it is just a programmable straightedge and compass. It is for implementing the geometrical constructions you see in instruments, furniture, paintings, and lots of Euclidean math exercises----you could figure out how to draw a square with a straightedge and compass, but how about a pentagon? (It can be done, exactly.)

What is specific to the program is my "pre coding" of a variety of constructions found in François Denis's remarkable book. Then you don't have to remember them, you just invoke them with the relevant parameters.

How are gouges, chisels and planes "directed specifically at violin makers and not woodworking in general"? There is a similar question for you. It's a tool, and every one of them has a learning curve accompanying it, the steepness of that curve determined by the tool, the user, and the task. I've used it to repeat François's constructions, and to do some new ones. The most complicated use so far is to draw the arching for a cello belly and back, guided by drawings in the Sacconi book.

Dear Harry,

Thanks for responding. I read your article in the Strad, thanks. I've been working with a ruler and compass since my first year in violin making school and I know very well how to draw a pentagon with a ruler and compass. That's easy. I will check into it and see if and how I can use it. I have Francois' book but I use a different system for violin design that is based on Kevin Coates groundbreaking book which analysed outlines of instruments.

Had it not been for the Stradivari forms, we would have designed the outline of the instrument which makes more sense to me. Just my opinion.

3 hours ago, Kevin Kelly said:

Last month I was sans computer for a week, and I had an encounter with an amazing violin, which I decided I had to "copy". This meant deconstructing the design, which I did using pencil and paper, but it took me about 4 hours. If I had my computer it would have taken less than 10 minutes - and I could have just printed out a drawing at the correct size to make a template from.

There are some parts of the program specifically for violin makers - for instance Harry has created a function that will add a margin to a finished mold shape, so if you draw the inside of the ribs it will create an outline based on that. You can also instruct it to measure between any parts of the drawings.

Hi Kevin,

Very interesting. Can I also design the outline and from it get the inner form? That's how I'd go about it.

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Very true, i am lazy. But one advantage with a drawing program is the built in measurement capability for me, to be able to instantly see what the radius or lengths are with just a click.

The advantages are many and unquestionable, it would be foolish not to exploit them nowadays, but the manual drawing ability is in any case irreplaceable if you consider yourself a luthier and not a geometer.

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The program that does the drawings is called the Geometry Engine, which is a program that Harry wrote. It's basically a digital version of a compass and straightedge, but you have to be able to describe the relationships between centers, arcs, and lines in mathematical terms.

The idea of a visual ruler and compass already exists in many forms, like SketchUp, for example - I've used that heavily, but you have to know how to dumb it down to use it because the defaults are for doing much more complicated 3D rendering. There are other free programs out there to do similar things, although it's been so many years since i looked I don't know what they are now.

The real benefit of using the Geometry Engine to me is that it is programmable, which means you can describe the relationships among the various parts of the drawing and then easily manipulate them. In other words, in the program that I use (I wrote my 'four circle' thing into the geo engine) I can, for example, change the width of the waist, which automatically changes the location of the points of the corners, which in turn changes the arcs of the curves of the corner blocks. To do this by hand takes some work, but on the computer it is just changing one number.

Last month I was sans computer for a week, and I had an encounter with an amazing violin, which I decided I had to "copy". This meant deconstructing the design, which I did using pencil and paper, but it took me about 4 hours. If I had my computer it would have taken less than 10 minutes - and I could have just printed out a drawing at the correct size to make a template from.

There are some parts of the program specifically for violin makers - for instance Harry has created a function that will add a margin to a finished mold shape, so if you draw the inside of the ribs it will create an outline based on that. You can also instruct it to measure between any parts of the drawings.

Now that I've copied the outline of a viola I am copying, using the hole in the box method, it would be very interesting to try arriving at the outline using Harry's program and compare the two. I suspect, given the precision offered by the program, there would be differences. But it would be an interesting exercise -- maybe one more incentive to learn to use Harry's contribution to our trade.

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Very interesting. Can I also design the outline and from it get the inner form? That's how I'd go about it.

How about a video demonstration to get us started?

Torbjörn

Hi Torbjörn,

I don't know about the first question, but I'm sure it's possible. I don't use the outline function myself.

As for the second one, no way. I'm all done with the video demonstrations. I did have Harry nearby to show me how to use it, though, and that really helped. I will admit that at first I was not interested in doing so, but I'm glad I eventually did.

50 minutes ago, Davide Sora said:

The advantages are many and unquestionable, it would be foolish not to exploit them nowadays, but the manual drawing ability is in any case irreplaceable if you consider yourself a luthier and not a geometer.

I agree. However, in the end the geo engine does the same thing as a divider and straightedge. It just saves a lot of time if you do a lot of drawings.

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Amplifying Kevin Kelly's comments, which are all on the mark, in response to Thorbjörn Zethelius: I've done the François Denis drawing course, because I wanted to know how to do these kinds of drawings by hand. Similarly, it's good to do operations by hand before you use power tools. Once you think that you sense what the real issues and challenges are, then you can think about appropriate mechanical advantages to surmount them.